Mitochondrial-Targeted Peptide

SS-31 (Elamipretide)

Mitochondria-targeted peptide with Phase II/III clinical trial data.

Cardiolipin stabilizationElectron transport chain (Complex I–IV)ROS/oxidative stressCytochrome c/apoptosis

59 B-

Evidence Score

ⓘ For informational purposes only — not medical advice.

Score Breakdown

Overview

SS-31 (elamipretide, Bendavia, MTP-131) is a mitochondria-targeted tetrapeptide that concentrates in the inner mitochondrial membrane. Developed by Stealth BioTherapeutics, it has undergone Phase II and III clinical trials for Barth syndrome, primary mitochondrial myopathy, and heart failure. It received FDA Rare Pediatric Disease designation for Barth syndrome.

Mechanism of Action

SS-31 selectively targets and stabilizes cardiolipin in the inner mitochondrial membrane. Cardiolipin is essential for electron transport chain complex organization and efficiency. By stabilizing cardiolipin, SS-31 improves mitochondrial bioenergetics, reduces electron leak and ROS production, and prevents cytochrome c release (apoptosis).

Evidence Base

Multiple Phase II and III clinical trials conducted by Stealth BioTherapeutics. TAZPOWER trial for Barth syndrome showed functional improvements. MMPOWER trials for primary mitochondrial myopathy showed mixed results. Phase II data in heart failure (EMBRACE) showed improvements in cardiac function biomarkers. FDA Rare Pediatric Disease designation granted.

Gene Pathway Detail

SS-31 stabilizes cardiolipin-dependent ETC complex assembly, affecting expression of nuclear-encoded mitochondrial genes (NDUFS subunits, SDHA, UQCRC2, COX subunits). Reduced ROS activates NRF2-mediated antioxidant gene expression and reduces NF-κB inflammatory signaling. Biomeme can monitor mitochondrial bioenergetic and oxidative stress gene signatures.

mRNA Monitoring Insight

Mitochondrial function genes and oxidative stress response targets are monitorable in peripheral blood. SS-31 provides one of the most amenable mitochondrial peptides for transcriptomic monitoring because its effects on nuclear-encoded mitochondrial genes should produce detectable mRNA changes systemically.

Safety Considerations

Extensive clinical trial safety data across multiple Phase II/III studies. Generally well-tolerated. Injection site reactions are the most common adverse effect. FDA Rare Pediatric Disease designation provides regulatory engagement. More safety data available than most peptides in this category.

FAQ

Is SS-31 available outside clinical trials?

SS-31 (elamipretide) is primarily available through clinical trials and compassionate use programs. It has not yet received FDA approval for any indication, though it has FDA Rare Pediatric Disease designation for Barth syndrome.

Quick Facts

Category: Mitochondrial-Targeted Peptide
Score: 59/100 (B-)
Gene Pathways: 4 characterized

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